Reference signal design for Pi/2 binary phase shift keying modulation with frequency domain spectral shaping

ABSTRACT

Certain aspects of the present disclosure relate to methods and apparatus relating to reference signal design for Pi/2-binary phase shift keying (Pi/2-BPSK) modulation with frequency domain spectral shaping (FDSS). In certain aspects, a method includes generating a set of Gold sequences each having a length and adjusting the length of each of the Gold sequences in the set of Gold sequences. The method also includes applying a phase rotation to each of the Gold sequences in the set of Gold sequences and modulating each of the Gold sequences in the set of Gold sequences by a DFT-s-OFDM with frequency domain spectral shaping (FDSS). The method further includes selecting one or more sequences from the set of modulated Gold sequences based on a parameter and transmitting the one or more sequences to a user equipment (UE) or a base station (BS).

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Application Ser. No.62/557,114 entitled “REFERENCE SIGNAL DESIGN FOR PI/2 BINARY PHASE SHIFTKEYING MODULATION WITH FREQUENCY DOMAIN SPECTRAL SHAPING,” which wasfiled Sep. 11, 2017. The aforementioned application is hereinincorporated by reference in its entirety.

INTRODUCTION

The present disclosure relates generally to communication systems, andmore particularly, to methods and apparatus relating to reference signaldesign for Pi/2-binary phase shift keying (Pi/2-BPSK) modulation withfrequency domain spectral shaping (FDSS).

Wireless communication systems are widely deployed to provide varioustelecommunication services such as telephony, video, data, messaging,and broadcasts. Typical wireless communication systems may employmultiple-access technologies capable of supporting communication withmultiple users by sharing available system resources (e.g., bandwidth,transmit power). Examples of such multiple-access technologies includeLong Term Evolution (LTE) systems, code division multiple access (CDMA)systems, time division multiple access (TDMA) systems, frequencydivision multiple access (FDMA) systems, orthogonal frequency divisionmultiple access (OFDMA) systems, single-carrier frequency divisionmultiple access (SC-FDMA) systems, and time division synchronous codedivision multiple access (TD-SCDMA) systems.

In some examples, a wireless multiple-access communication system mayinclude a number of base stations, each simultaneously supportingcommunication for multiple communication devices, otherwise known asuser equipment (UEs). In LTE or LTE-A network, a set of one or more basestations may define an e NodeB (eNB). In other examples (e.g., in a nextgeneration or 5G network), a wireless multiple access communicationsystem may include a number of distributed units (DUs) (e.g., edge units(EUs), edge nodes (ENs), radio heads (RHs), smart radio heads (SRHs),transmission reception points (TRPs), etc.) in communication with anumber of central units (CUs) (e.g., central nodes (CNs), access nodecontrollers (ANCs), etc.), where a set of one or more distributed units,in communication with a central unit, may define an access node (e.g., anew radio base station (NR BS), a new radio node-B (NR NB), a networknode, 5G NB, gNB, gNodeB, eNB, etc.). A base station or DU maycommunicate with a set of UEs on downlink channels (e.g., fortransmissions from a base station or to a UE) and uplink channels (e.g.,for transmissions from a UE to a base station or distributed unit).

These multiple access technologies have been adopted in varioustelecommunication standards to provide a common protocol that enablesdifferent wireless devices to communicate on a municipal, national,regional, and even global level. An example of an emergingtelecommunication standard is new radio (NR), for example, 5G radioaccess. NR is a set of enhancements to the LTE mobile standardpromulgated by Third Generation Partnership Project (3GPP). It isdesigned to better support mobile broadband Internet access by improvingspectral efficiency, lowering costs, improving services, making use ofnew spectrum, and better integrating with other open standards usingOFDMA with a cyclic prefix (CP) on the downlink (DL) and on the uplink(UL) as well as support beamforming, multiple-input multiple-output(MIMO) antenna technology, and carrier aggregation.

However, as the demand for mobile broadband access continues toincrease, there exists a need for further improvements in NR technology.Preferably, these improvements should be applicable to othermulti-access technologies and the telecommunication standards thatemploy these technologies.

BRIEF SUMMARY

The systems, methods, and devices of the disclosure each have severalaspects, no single one of which is solely responsible for its desirableattributes. Without limiting the scope of this disclosure as expressedby the claims which follow, some features will now be discussed briefly.After considering this discussion, and particularly after reading thesection entitled “Detailed Description” one will understand how thefeatures of this disclosure provide advantages that include improvedcommunications between access points and stations in a wireless network.

Certain aspects provide a method for wireless communications. The methodincludes generating a set of Gold sequences each having a length. Themethod also includes adjusting the length of each of the Gold sequencesin the set of Gold sequences. The method further includes applying aphase rotation to each of the Gold sequences in the set of Goldsequences. The method also includes modulating each of the of the Goldsequences in the set of Gold sequences by a Pi/2 binary phase shiftkeying modulation (BPSK) modulation with frequency domain spectralshaping. The method further includes selecting one or more sequencesfrom the set of modulated Gold sequences based on a parameter. Themethod also includes transmitting the one or more sequences to a userequipment (UE) or a base station (BS).

Also described herein are embodiments of an apparatus comprising anon-transitory memory comprising executable instructions and a processorin data communication with the memory and configured to execute theinstructions to generate a set of Gold sequences each having a length,adjust the length of each of the Gold sequences in the set of Goldsequences, apply a phase rotation to each of the Gold sequences in theset of Gold sequences, modulate each of the of the Gold sequences in theset of Gold sequences by a DFT-s-OFDM with frequency domain spectralshaping (FDSS), select one or more sequences from the set of modulatedGold sequences based on a parameter, and transmit the one or moresequences to a user equipment (UE) or a base station (BS).

Also described herein are embodiments of an apparatus comprising meansfor generating a set of Gold sequences each having a length, means foradjusting the length of each of the Gold sequences in the set of Goldsequences, means for applying a phase rotation to each of the Goldsequences in the set of Gold sequences, means for modulating each of theof the Gold sequences in the set of Gold sequences by a DFT-s-OFDM withfrequency domain spectral shaping (FDSS), means for selecting one ormore sequences from the set of modulated Gold sequences based on aparameter, and means for transmitting the one or more sequences to auser equipment (UE) or a base station (BS).

Also described herein are embodiments of a non-transitory computerreadable medium comprising instructions to be executed in a computersystem, wherein the instructions when executed in the computer systemperform a method for wireless communications, the method comprising:generating a set of Gold sequences each having a length, adjusting thelength of each of the Gold sequences in the set of Gold sequences,applying a phase rotation to each of the Gold sequences in the set ofGold sequences, modulating each of the of the Gold sequences in the setof Gold sequences by a DFT-s-OFDM with frequency domain spectral shaping(FDSS), selecting one or more sequences from the set of modulated Goldsequences based on a parameter, and transmitting the one or moresequences to a user equipment (UE) or a base station (BS).

Aspects generally include methods, apparatus, systems, computer readablemediums, and processing systems, as substantially described herein withreference to and as illustrated by the accompanying drawings.

To the accomplishment of the foregoing and related ends, the one or moreaspects comprise the features hereinafter fully described andparticularly pointed out in the claims. The following description andthe annexed drawings set forth in detail certain illustrative featuresof the one or more aspects. These features are indicative, however, ofbut a few of the various ways in which the principles of various aspectsmay be employed, and this description is intended to include all suchaspects and their equivalents.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above-recited features of the presentdisclosure can be understood in detail, a more particular description,briefly summarized above, may be had by reference to aspects, some ofwhich are illustrated in the appended drawings. It is to be noted,however, that the appended drawings illustrate only certain typicalaspects of this disclosure and are therefore not to be consideredlimiting of its scope, for the description may admit to other equallyeffective aspects.

FIG. 1 is a block diagram conceptually illustrating an exampletelecommunications system, in accordance with certain aspects of thepresent disclosure.

FIG. 2 is a block diagram illustrating an example logical architectureof a distributed RAN, in accordance with certain aspects of the presentdisclosure.

FIG. 3 is a diagram illustrating an example physical architecture of adistributed RAN, in accordance with certain aspects of the presentdisclosure.

FIG. 4 is a block diagram conceptually illustrating a design of anexample BS and user equipment (UE), in accordance with certain aspectsof the present disclosure.

FIG. 5 is a diagram showing examples for implementing a communicationprotocol stack, in accordance with certain aspects of the presentdisclosure.

FIG. 6 illustrates an example of a DL-centric subframe, in accordancewith certain aspects of the present disclosure.

FIG. 7 illustrates an example of an UL-centric subframe, in accordancewith certain aspects of the present disclosure.

FIG. 8 illustrates example operations for wireless communications, inaccordance with certain aspects.

FIG. 9 illustrates an example flow diagram for modulating a Goldsequence, in accordance with certain aspects of the present disclosure.

FIG. 10 illustrates an example communications device that may includevarious components configured to perform operations for the techniquesdisclosed herein, such as one or more of the operations illustrated inFIG. 8.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. It is contemplated that elements disclosed in one aspectmay be beneficially utilized on other aspects without specificrecitation.

DETAILED DESCRIPTION

Aspects of the present disclosure relate to methods and apparatusrelating to reference signal designs for pi/2-binary phase shift keying(BPSK) modulation with frequency domain spectral shaping (FDSS).

Aspects of the present disclosure provide apparatus, methods, processingsystems, and computer readable mediums for new radio (NR) (new radioaccess technology or 5G technology).

NR may support various wireless communication services, such as Enhancedmobile broadband (eMBB) targeting wide bandwidth (e.g. 80 MHz beyond),millimeter wave (mmW) targeting high carrier frequency (e.g. 60 GHz),massive MTC (mMTC) targeting non-backward compatible MTC techniques,and/or mission critical targeting ultra reliable low latencycommunications (URLLC). These services may include latency andreliability requirements. These services may also have differenttransmission time intervals (TTI) to meet respective quality of service(QoS) requirements. In addition, these services may co-exist in the samesubframe.

Aspects of the present disclosure relate to using Gold sequences fordesigning a reference signal for Pi/2-binary phase shift keying (BPSK)modulation with frequency domain spectral shaping (FDSS). The use ofGold sequences for designing a reference signal for Pi/2 BPSK with FDSSaddresses the extremely low peak-to-average ratio (PAPR) associated withPi/2 BPSK modulation with FDSS. Using a Gold Sequence here isadvantageous because of its good Cyclic-Autocorrelation Property andalso its frequency domain flatness.

The following description provides examples, and is not limiting of thescope, applicability, or examples set forth in the claims. Changes maybe made in the function and arrangement of elements discussed withoutdeparting from the scope of the disclosure. Various examples may omit,substitute, or add various procedures or components as appropriate. Forinstance, the methods described may be performed in an order differentfrom that described, and various steps may be added, omitted, orcombined. Also, features described with respect to some examples may becombined in some other examples. For example, an apparatus may beimplemented or a method may be practiced using any number of the aspectsset forth herein. In addition, the scope of the disclosure is intendedto cover such an apparatus or method which is practiced using otherstructure, functionality, or structure and functionality in addition toor other than the various aspects of the disclosure set forth herein. Itshould be understood that any aspect of the disclosure disclosed hereinmay be embodied by one or more elements of a claim. The word “exemplary”is used herein to mean “serving as an example, instance, orillustration.” Any aspect described herein as “exemplary” is notnecessarily to be construed as preferred or advantageous over otheraspects.

The techniques described herein may be used for various wirelesscommunication networks such as LTE, CDMA, TDMA, FDMA, OFDMA, SC-FDMA andother networks. The terms “network” and “system” are often usedinterchangeably. A CDMA network may implement a radio technology such asUniversal Terrestrial Radio Access (UTRA), cdma2000, etc. UTRA includesWideband CDMA (WCDMA) and other variants of CDMA. cdma2000 coversIS-2000, IS-95 and IS-856 standards. A TDMA network may implement aradio technology such as Global System for Mobile Communications (GSM).An OFDMA network may implement a radio technology such as NR (e.g. 5GRA), Evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11(Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDMA, etc. UTRA andE-UTRA are part of Universal Mobile Telecommunication System (UMTS). NRis an emerging wireless communications technology under development inconjunction with the 5G Technology Forum (5GTF). 3GPP Long TermEvolution (LTE) and LTE-Advanced (LTE-A) are releases of UMTS that useE-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A and GSM are described indocuments from an organization named “3rd Generation PartnershipProject” (3GPP). cdma2000 and UMB are described in documents from anorganization named “3rd Generation Partnership Project 2” (3GPP2). Thetechniques described herein may be used for the wireless networks andradio technologies mentioned above as well as other wireless networksand radio technologies. For clarity, while aspects may be describedherein using terminology commonly associated with 3G and/or 4G wirelesstechnologies, aspects of the present disclosure can be applied in othergeneration-based communication systems, such as 5G and later, includingNR technologies.

Example Wireless Communications System

FIG. 1 illustrates an example wireless network 100, such as a new radio(NR) or 5G network, in which aspects of the present disclosure may beperformed. For example, base station (BS) 110 may perform operations 800of FIG. 8. In another example, user equipment (UE) 120 may performoperations 800 of FIG. 8.

As illustrated in FIG. 1, the wireless network 100 may include a numberof BSs 110 and other network entities. A BS may be a station thatcommunicates with UEs. Each BS 110 may provide communication coveragefor a particular geographic area. In 3GPP, the term “cell” can refer toa coverage area of a Node B and/or a Node B subsystem serving thiscoverage area, depending on the context in which the term is used. In NRsystems, the term “cell” and eNB, gNB, gNodeB, Node B, 5G NB, AP, NR BS,NR BS, or TRP may be interchangeable. In some examples, a cell may notnecessarily be stationary, and the geographic area of the cell may moveaccording to the location of a mobile base station. In some examples,the base stations may be interconnected to one another and/or to one ormore other base stations or network nodes (not shown) in the wirelessnetwork 100 through various types of backhaul interfaces such as adirect physical connection, a virtual network, or the like using anysuitable transport network.

In general, any number of wireless networks may be deployed in a givengeographic area. Each wireless network may support a particular radioaccess technology (RAT) and may operate on one or more frequencies. ARAT may also be referred to as a radio technology, an air interface,etc. A frequency may also be referred to as a carrier, a frequencychannel, etc. Each frequency may support a single RAT in a givengeographic area in order to avoid interference between wireless networksof different RATs. In some cases, NR or 5G RAT networks may be deployed.

A BS may provide communication coverage for a macro cell, a pico cell, afemto cell, and/or other types of cell. A macro cell may cover arelatively large geographic area (e.g., several kilometers in radius)and may allow unrestricted access by UEs with service subscription. Apico cell may cover a relatively small geographic area and may allowunrestricted access by UEs with service subscription. A femto cell maycover a relatively small geographic area (e.g., a home) and may allowrestricted access by UEs having association with the femto cell (e.g.,UEs in a Closed Subscriber Group (CSG), UEs for users in the home,etc.). A BS for a macro cell may be referred to as a macro BS. A BS fora pico cell may be referred to as a pico BS. A BS for a femto cell maybe referred to as a femto BS or a home BS. In the example shown in FIG.1, the BSs 110 a, 110 b and 110 c may be macro BSs for the macro cells102 a, 102 b and 102 c, respectively. The BS 110 x may be a pico BS fora pico cell 102 x. The BSs 110 y and 110 z may be femto BS for the femtocells 102 y and 102 z, respectively. A BS may support one or multiple(e.g., three) cells.

The wireless network 100 may also include relay stations. A relaystation is a station that receives a transmission of data and/or otherinformation from an upstream station (e.g., a BS or a UE) and sends atransmission of the data and/or other information to a downstreamstation (e.g., a UE or a BS). A relay station may also be a UE thatrelays transmissions for other UEs. In the example shown in FIG. 1, arelay station 110 r may communicate with the BS 110 a and a UE 120 r inorder to facilitate communication between the BS 110 a and the UE 120 r.A relay station may also be referred to as a relay BS, a relay, etc.

The wireless network 100 may be a heterogeneous network that includesBSs of different types, e.g., macro BS, pico BS, femto BS, relays, etc.These different types of BSs may have different transmit power levels,different coverage areas, and different impact on interference in thewireless network 100. For example, macro BS may have a high transmitpower level (e.g., 20 Watts) whereas pico BS, femto BS, and relays mayhave a lower transmit power level (e.g., 1 Watt).

The wireless network 100 may support synchronous or asynchronousoperation. For synchronous operation, the BSs may have similar frametiming, and transmissions from different BSs may be approximatelyaligned in time. For asynchronous operation, the BSs may have differentframe timing, and transmissions from different BSs may not be aligned intime. The techniques described herein may be used for both synchronousand asynchronous operation.

A network controller 130 may be coupled to a set of BSs and providecoordination and control for these BSs. The network controller 130 maycommunicate with the BSs 110 via a backhaul. The BSs 110 may alsocommunicate with one another, e.g., directly or indirectly via wirelessor wireline backhaul.

The UEs 120 (e.g., 120 x, 120 y, etc.) may be dispersed throughout thewireless network 100, and each UE may be stationary or mobile. A UE mayalso be referred to as a mobile station, a terminal, an access terminal,a subscriber unit, a station, a Customer Premises Equipment (CPE), acellular phone, a smart phone, a personal digital assistant (PDA), awireless modem, a wireless communication device, a handheld device, alaptop computer, a cordless phone, a wireless local loop (WLL) station,a tablet, a camera, a gaming device, a netbook, a smartbook, anultrabook, a medical device or medical equipment, a biometricsensor/device, a wearable device such as a smart watch, smart clothing,smart glasses, a smart wrist band, smart jewelry (e.g., a smart ring, asmart bracelet, etc.), an entertainment device (e.g., a music device, avideo device, a satellite radio, etc.), a vehicular component or sensor,a smart meter/sensor, industrial manufacturing equipment, a globalpositioning system device, or any other suitable device that isconfigured to communicate via a wireless or wired medium. Some UEs maybe considered evolved or machine-type communication (MTC) devices orevolved MTC (eMTC) devices. MTC and eMTC UEs include, for example,robots, drones, remote devices, sensors, meters, monitors, locationtags, etc., that may communicate with a BS, another device (e.g., remotedevice), or some other entity. A wireless node may provide, for example,connectivity for or to a network (e.g., a wide area network such asInternet or a cellular network) via a wired or wireless communicationlink. Some UEs may be considered Internet-of-Things (IoT) devices.

In FIG. 1, a solid line with double arrows indicates desiredtransmissions between a UE and a serving BS, which is a BS designated toserve the UE on the downlink and/or uplink. A dashed line with doublearrows indicates interfering transmissions between a UE and a BS.

In certain aspects, as shown, a UE 120 may be configured to managebuffers of the UE 120 to store encoded data and the BS 110 may beconfigured to transmit encoded data to the UE 120 based on an assumptionthe UE 120 is managing the buffers, according to the techniquesdiscussed herein.

Certain wireless networks (e.g., LTE) utilize orthogonal frequencydivision multiplexing (OFDM) on the downlink and single-carrierfrequency division multiplexing (SC-FDM) on the uplink. OFDM and SC-FDMpartition the system bandwidth into multiple (K) orthogonal subcarriers,which are also commonly referred to as tones, bins, etc. Each subcarriermay be modulated with data. In general, modulation symbols are sent inthe frequency domain with OFDM and in the time domain with SC-FDM. Thespacing between adjacent subcarriers may be fixed, and the total numberof subcarriers (K) may be dependent on the system bandwidth. Forexample, the spacing of the subcarriers may be 15 kHz and the minimumresource allocation (called a ‘resource block’) may be 12 subcarriers(or 180 kHz). Consequently, the nominal FFT size may be equal to 128,256, 512, 1024 or 2048 for system bandwidth of 1.25, 2.5, 5, 10 or 20megahertz (MHz), respectively. The system bandwidth may also bepartitioned into subbands. For example, a subband may cover 1.08 MHz(i.e., 6 resource blocks), and there may be 1, 2, 4, 8 or 16 subbandsfor system bandwidth of 1.25, 2.5, 5, 10 or 20 MHz, respectively.

While aspects of the examples described herein may be associated withLTE technologies, aspects of the present disclosure may be applicablewith other wireless communications systems, such as NR. NR may utilizeOFDM with a CP on the uplink and downlink and include support forhalf-duplex operation using time division duplex (TDD). A singlecomponent carrier bandwidth of 100 MHz may be supported. NR resourceblocks may span 12 sub-carriers with a sub-carrier bandwidth of 75 kHzover a 0.1 ms duration. Each radio frame may consist of 50 subframeswith a length of 10 ms. Consequently, each subframe may have a length of0.2 ms. Each subframe may indicate a link direction (i.e., DL or UL) fordata transmission and the link direction for each subframe may bedynamically switched. Each subframe may include DL/UL data as well asDL/UL control data. UL and DL subframes for NR may be as described inmore detail below. Beamforming may be supported and beam direction maybe dynamically configured. MIMO transmissions with precoding may also besupported. MIMO configurations in the DL may support up to 8 transmitantennas with multi-layer DL transmissions up to 8 streams and up to 2streams per UE. Multi-layer transmissions with up to 2 streams per UEmay be supported. Aggregation of multiple cells may be supported with upto 8 serving cells. Alternatively, NR may support a different airinterface, other than an OFDM-based. NR networks may include entitiessuch CUs and/or DUs.

In some examples, access to the air interface may be scheduled, whereina scheduling entity (e.g., a base station) allocates resources forcommunication among some or all devices and equipment within its servicearea or cell. Within the present disclosure, as discussed further below,the scheduling entity may be responsible for scheduling, assigning,reconfiguring, and releasing resources for one or more subordinateentities. That is, for scheduled communication, subordinate entitiesutilize resources allocated by the scheduling entity. Base stations arenot the only entities that may function as a scheduling entity. That is,in some examples, a UE may function as a scheduling entity, schedulingresources for one or more subordinate entities (e.g., one or more otherUEs). In this example, the UE is functioning as a scheduling entity, andother UEs utilize resources scheduled by the UE for wirelesscommunication. A UE may function as a scheduling entity in apeer-to-peer (P2P) network, and/or in a mesh network. In a mesh networkexample, UEs may optionally communicate directly with one another inaddition to communicating with the scheduling entity.

Thus, in a wireless communication network with a scheduled access totime-frequency resources and having a cellular configuration, a P2Pconfiguration, and a mesh configuration, a scheduling entity and one ormore subordinate entities may communicate utilizing the scheduledresources.

As noted above, a RAN may include a CU and DUs. A NR BS (e.g., eNB, 5GNode B, Node B, transmission reception point (TRP), access point (AP))may correspond to one or multiple BSs. NR cells can be configured asaccess cell (ACells) or data only cells (DCells). For example, the RAN(e.g., a central unit or distributed unit) can configure the cells.DCells may be cells used for carrier aggregation or dual connectivity,but not used for initial access, cell selection/reselection, orhandover. In some cases DCells may not transmit synchronizationsignals—in some case cases DCells may transmit SS. NR BSs may transmitdownlink signals to UEs indicating the cell type. Based on the cell typeindication, the UE may communicate with the NR BS. For example, the UEmay determine NR BSs to consider for cell selection, access, handover,and/or measurement based on the indicated cell type.

FIG. 2 illustrates an example logical architecture of a distributedradio access network (RAN) 200, which may be implemented in the wirelesscommunication system illustrated in FIG. 1. A 5G access node 206 mayinclude an access node controller (ANC) 202. The ANC may be a centralunit (CU) of the distributed RAN 200. The backhaul interface to the nextgeneration core network (NG-CN) 204 may terminate at the ANC. Thebackhaul interface to neighboring next generation access nodes (NG-ANs)may terminate at the ANC. The ANC may include one or more TRPs 208(which may also be referred to as BSs, NR BSs, Node Bs, 5G NBs, APs, orsome other term). As described above, a TRP may be used interchangeablywith “cell.”

The TRPs 208 may be a DU. The TRPs may be connected to one ANC (ANC 202)or more than one ANC (not illustrated). For example, for RAN sharing,radio as a service (RaaS), and service specific AND deployments, the TRPmay be connected to more than one ANC. A TRP may include one or moreantenna ports. The TRPs may be configured to individually (e.g., dynamicselection) or jointly (e.g., joint transmission) serve traffic to a UE.

The local architecture 200 may be used to illustrate fronthauldefinition. The architecture may be defined that support fronthaulingsolutions across different deployment types. For example, thearchitecture may be based on transmit network capabilities (e.g.,bandwidth, latency, and/or jitter).

The architecture may share features and/or components with LTE.According to aspects, the next generation AN (NG-AN) 210 may supportdual connectivity with NR. The NG-AN may share a common fronthaul forLTE and NR.

The architecture may enable cooperation between and among TRPs 208. Forexample, cooperation may be preset within a TRP and/or across TRPs viathe ANC 202. According to aspects, no inter-TRP interface may beneeded/present.

According to aspects, a dynamic configuration of split logical functionsmay be present within the architecture 200. As will be described in moredetail with reference to FIG. 5, the Radio Resource Control (RRC) layer,Packet Data Convergence Protocol (PDCP) layer, Radio Link Control (RLC)layer, Medium Access Control (MAC) layer, and a Physical (PHY) layersmay be adaptably placed at the DU or CU (e.g., TRP or ANC,respectively). According to certain aspects, a BS may include a centralunit (CU) (e.g., ANC 202) and/or one or more distributed units (e.g.,one or more TRPs 208).

FIG. 3 illustrates an example physical architecture of a distributed RAN300, according to aspects of the present disclosure. A centralized corenetwork unit (C-CU) 302 may host core network functions. The C-CU may becentrally deployed. C-CU functionality may be offloaded (e.g., toadvanced wireless services (AWS)), in an effort to handle peak capacity.

A centralized RAN unit (C-RU) 304 may host one or more ANC functions.Optionally, the C-RU may host core network functions locally. The C-RUmay have distributed deployment. The C-RU may be closer to the networkedge.

A DU 306 may host one or more TRPs (edge node (EN), an edge unit (EU), aradio head (RH), a smart radio head (SRH), or the like). The DU may belocated at edges of the network with radio frequency (RF) functionality.

FIG. 4 illustrates example components of the BS 110 and UE 120illustrated in FIG. 1, which may be used to implement aspects of thepresent disclosure. As described above, the BS may include a TRP. One ormore components of the BS 110 and UE 120 may be used to practice aspectsof the present disclosure. For example, antennas 452, Tx/Rx 222,processors 466, 458, 464, and/or controller/processor 480 of the UE 120and/or antennas 434, processors 460, 420, 438, and/orcontroller/processor 440 of the BS 110 may be used to perform theoperations described herein.

FIG. 4 shows a block diagram of a design of a BS 110 and a UE 120, whichmay be one of the BSs and one of the UEs in FIG. 1. For a restrictedassociation scenario, the base station 110 may be the macro BS 110 c inFIG. 1, and the UE 120 may be the UE 120 y. The base station 110 mayalso be a base station of some other type. The base station 110 may beequipped with antennas 434 a through 434 t, and the UE 120 may beequipped with antennas 452 a through 452 r.

At the base station 110, a transmit processor 420 may receive data froma data source 412 and control information from a controller/processor440. The control information may be for the Physical Broadcast Channel(PBCH), Physical Control Format Indicator Channel (PCFICH), PhysicalHybrid ARQ Indicator Channel (PHICH), Physical Downlink Control Channel(PDCCH), etc. The data may be for the Physical Downlink Shared Channel(PDSCH), etc. The processor 420 may process (e.g., encode and symbolmap) the data and control information to obtain data symbols and controlsymbols, respectively. The processor 420 may also generate referencesymbols, e.g., for the PSS, SSS, DMRS, and cell-specific referencesignal. A transmit (TX) multiple-input multiple-output (MIMO) processor430 may perform spatial processing (e.g., precoding) on the datasymbols, the control symbols, and/or the reference symbols, ifapplicable, and may provide output symbol streams to the modulators(MODs) 432 a through 432 t. Each modulator 432 may process a respectiveoutput symbol stream (e.g., for OFDM, etc.) to obtain an output samplestream. Each modulator 432 may further process (e.g., convert to analog,amplify, filter, and upconvert) the output sample stream to obtain adownlink signal. Downlink signals from modulators 432 a through 432 tmay be transmitted via the antennas 434 a through 434 t, respectively.

At the UE 120, the antennas 452 a through 452 r may receive the downlinksignals from the base station 110 and may provide received signals tothe demodulators (DEMODs) 454 a through 454 r, respectively. Eachdemodulator 454 may condition (e.g., filter, amplify, downconvert, anddigitize) a respective received signal to obtain input samples. Eachdemodulator 454 may further process the input samples (e.g., for OFDM,etc.) to obtain received symbols. A MIMO detector 456 may obtainreceived symbols from all the demodulators 454 a through 454 r, performMIMO detection on the received symbols if applicable, and providedetected symbols. A receive processor 458 may process (e.g., demodulate,deinterleave, and decode) the detected symbols, provide decoded data forthe UE 120 to a data sink 460, and provide decoded control informationto a controller/processor 480.

On the uplink, at the UE 120, a transmit processor 464 may receive andprocess data (e.g., for the Physical Uplink Shared Channel (PUSCH)) froma data source 462 and control information (e.g., for the Physical UplinkControl Channel (PUCCH) from the controller/processor 480. The transmitprocessor 464 may also generate reference symbols for a referencesignal. The symbols from the transmit processor 464 may be precoded by aTX MIMO processor 466 if applicable, further processed by thedemodulators 454 a through 454 r (e.g., for SC-FDM, etc.), andtransmitted to the base station 110. At the BS 110, the uplink signalsfrom the UE 120 may be received by the antennas 434, processed by themodulators 432, detected by a MIMO detector 436 if applicable, andfurther processed by a receive processor 438 to obtain decoded data andcontrol information sent by the UE 120. The receive processor 438 mayprovide the decoded data to a data sink 439 and the decoded controlinformation to the controller/processor 440.

The controllers/processors 440 and 480 may direct the operation at thebase station 110 and the UE 120, respectively. The processor 440 and/orother processors and modules at the base station 110 may perform ordirect processes for the techniques described herein (e.g., operation800 of FIG. 8). The processor 480 and/or other processors and modules atthe UE 120 may also perform or direct processes for the techniquesdescribed herein (e.g., operation 800 of FIG. 8). The memories 442 and482 may store data and program codes for the BS 110 and the UE 120,respectively. A scheduler 444 may schedule UEs for data transmission onthe downlink and/or uplink.

FIG. 5 illustrates a diagram 500 showing examples for implementing acommunications protocol stack, according to aspects of the presentdisclosure. The illustrated communications protocol stacks may beimplemented by devices operating in a in a 5G system (e.g., a systemthat supports uplink-based mobility). Diagram 500 illustrates acommunications protocol stack including a Radio Resource Control (RRC)layer 510, a Packet Data Convergence Protocol (PDCP) layer 515, a RadioLink Control (RLC) layer 520, a Medium Access Control (MAC) layer 525,and a Physical (PHY) layer 530. In various examples the layers of aprotocol stack may be implemented as separate modules of software,portions of a processor or ASIC, portions of non-collocated devicesconnected by a communications link, or various combinations thereof.Collocated and non-collocated implementations may be used, for example,in a protocol stack for a network access device (e.g., ANs, CUs, and/orDUs) or a UE.

A first option 505-a shows a split implementation of a protocol stack,in which implementation of the protocol stack is split between acentralized network access device (e.g., an ANC 202 in FIG. 2) anddistributed network access device (e.g., DU 208 in FIG. 2). In the firstoption 505-a, an RRC layer 510 and a PDCP layer 515 may be implementedby the central unit, and an RLC layer 520, a MAC layer 525, and a PHYlayer 530 may be implemented by the DU. In various examples the CU andthe DU may be collocated or non-collocated. The first option 505-a maybe useful in a macro cell, micro cell, or pico cell deployment.

A second option 505-b shows a unified implementation of a protocolstack, in which the protocol stack is implemented in a single networkaccess device (e.g., access node (AN), new radio base station (NR BS), anew radio Node-B (NR NB), a network node (NN), or the like). In thesecond option, the RRC layer 510, the PDCP layer 515, the RLC layer 520,the MAC layer 525, and the PHY layer 530 may each be implemented by theAN. The second option 505-b may be useful in a femto cell deployment.

Regardless of whether a network access device implements part or all ofa protocol stack, a UE may implement an entire protocol stack (e.g., theRRC layer 510, the PDCP layer 515, the RLC layer 520, the MAC layer 525,and the PHY layer 530).

FIG. 6 is a diagram 600 showing an example of a DL-centric subframe. TheDL-centric subframe may include a control portion 602. The controlportion 602 may exist in the initial or beginning portion of theDL-centric subframe. The control portion 602 may include variousscheduling information and/or control information corresponding tovarious portions of the DL-centric subframe. In some configurations, thecontrol portion 602 may be a physical DL control channel (PDCCH), asindicated in FIG. 6. The DL-centric subframe may also include a DL dataportion 604. The DL data portion 604 may sometimes be referred to as thepayload of the DL-centric subframe. The DL data portion 604 may includethe communication resources utilized to communicate DL data from thescheduling entity (e.g., UE or BS) to the subordinate entity (e.g., UE).In some configurations, the DL data portion 604 may be a physical DLshared channel (PDSCH).

The DL-centric subframe may also include a common UL portion 606. Thecommon UL portion 606 may sometimes be referred to as an UL burst, acommon UL burst, and/or various other suitable terms. The common ULportion 606 may include feedback information corresponding to variousother portions of the DL-centric subframe. For example, the common ULportion 606 may include feedback information corresponding to thecontrol portion 602. Non-limiting examples of feedback information mayinclude an ACK signal, a NACK signal, a HARQ indicator, and/or variousother suitable types of information. The common UL portion 606 mayinclude additional or alternative information, such as informationpertaining to random access channel (RACH) procedures, schedulingrequests (SRs), and various other suitable types of information. Asillustrated in FIG. 6, the end of the DL data portion 604 may beseparated in time from the beginning of the common UL portion 606. Thistime separation may sometimes be referred to as a gap, a guard period, aguard interval, and/or various other suitable terms. This separationprovides time for the switch-over from DL communication (e.g., receptionoperation by the subordinate entity (e.g., UE)) to UL communication(e.g., transmission by the subordinate entity (e.g., UE)). One ofordinary skill in the art will understand that the foregoing is merelyone example of a DL-centric subframe and alternative structures havingsimilar features may exist without necessarily deviating from theaspects described herein.

FIG. 7 is a diagram 700 showing an example of an UL-centric subframe.The UL-centric subframe may include a control portion 702. The controlportion 702 may exist in the initial or beginning portion of theUL-centric subframe. The control portion 702 in FIG. 7 may be similar tothe control portion described above with reference to FIG. 6. TheUL-centric subframe may also include an UL data portion 704. The UL dataportion 704 may sometimes be referred to as the payload of theUL-centric subframe. The UL portion may refer to the communicationresources utilized to communicate UL data from the subordinate entity(e.g., UE) to the scheduling entity (e.g., UE or BS). In someconfigurations, the control portion 702 may be a physical DL controlchannel (PDCCH).

As illustrated in FIG. 7, the end of the control portion 702 may beseparated in time from the beginning of the UL data portion 704. Thistime separation may sometimes be referred to as a gap, guard period,guard interval, and/or various other suitable terms. This separationprovides time for the switch-over from DL communication (e.g., receptionoperation by the scheduling entity) to UL communication (e.g.,transmission by the scheduling entity). The UL-centric subframe may alsoinclude a common UL portion 706. The common UL portion 706 in FIG. 7 maybe similar to the common UL portion 706 described above with referenceto FIG. 7. The common UL portion 706 may additional or alternativeinclude information pertaining to channel quality indicator (CQI),sounding reference signals (SRSs), and various other suitable types ofinformation. One of ordinary skill in the art will understand that theforegoing is merely one example of an UL-centric subframe andalternative structures having similar features may exist withoutnecessarily deviating from the aspects described herein.

In some circumstances, two or more subordinate entities (e.g., UEs) maycommunicate with each other using sidelink signals. Real-worldapplications of such sidelink communications may include public safety,proximity services, UE-to-network relaying, vehicle-to-vehicle (V2V)communications, Internet of Everything (IoE) communications, IoTcommunications, mission-critical mesh, and/or various other suitableapplications. Generally, a sidelink signal may refer to a signalcommunicated from one subordinate entity (e.g., UE1) to anothersubordinate entity (e.g., UE2) without relaying that communicationthrough the scheduling entity (e.g., UE or BS), even though thescheduling entity may be utilized for scheduling and/or controlpurposes. In some examples, the sidelink signals may be communicatedusing a licensed spectrum (unlike wireless local area networks, whichtypically use an unlicensed spectrum).

A UE may operate in various radio resource configurations, including aconfiguration associated with transmitting pilots using a dedicated setof resources (e.g., a radio resource control (RRC) dedicated state,etc.) or a configuration associated with transmitting pilots using acommon set of resources (e.g., an RRC common state, etc.). Whenoperating in the RRC dedicated state, the UE may select a dedicated setof resources for transmitting a pilot signal to a network. Whenoperating in the RRC common state, the UE may select a common set ofresources for transmitting a pilot signal to the network. In eithercase, a pilot signal transmitted by the UE may be received by one ormore network access devices, such as an AN, or a DU, or portionsthereof. Each receiving network access device may be configured toreceive and measure pilot signals transmitted on the common set ofresources, and also receive and measure pilot signals transmitted ondedicated sets of resources allocated to the UEs for which the networkaccess device is a member of a monitoring set of network access devicesfor the UE. One or more of the receiving network access devices, or a CUto which receiving network access device(s) transmit the measurements ofthe pilot signals, may use the measurements to identify serving cellsfor the UEs, or to initiate a change of serving cell for one or more ofthe UEs.

Example Reference Signal Design for Pi/2 Binary Phase Shift KeyingModulation with Frequency Domain Spectral Shaping

In some cases, Pi/2 BPSK (binary phase shift keying) modulation withFDSS (frequency domain spectral shaping) has extremely lowpeak-to-average power ratio (PAPR). Therefore, it is important to designa reference signal for Pi/2-BPSK modulation with FDSS for channelestimation for signals that use Pi/2-BPSK modulation with FDSS. In someembodiments, a Gold sequence may be used for designing the referencesignal for Pi/2-BPSK modulation with FDSS. A Gold sequence is a type ofbinary sequence that is defined using a specified pair of sequences uand v, of period N=2^(n)-1, called a preferred pair. Using a GoldSequence is advantageous because of its good Cyclic-AutocorrelationProperty and also its frequency domain flatness. However, a Goldsequence is not modulated by Pi/2-BPSK (e.g., a Gold sequence is a +1/−1sequence, while a Pi/2-BPSK sequence includes imaginary elements). Also,the length of a Gold sequence is limited to 2{circumflex over ( )}n−1(e.g., 3, 7, 15, 63, . . . ).

Accordingly, certain embodiments described herein relate to using Goldsequences to generate a reference signal having a design for Pi/2-BPSKmodulation with FDSS.

FIG. 8 illustrates example operations 800 for wireless communications,in accordance with certain aspects. According to certain aspects,operations 800 may be performed by a BS (e.g., one or more of the BSs110). According to certain other aspects, operations 800 may beperformed by a UE (e.g., one or more of the UEs 120).

Operations 800 begin at 802 by generating a set of Gold sequences eachhaving a length. At 804, operations 800 continue by adjusting the lengthof each of the Gold sequences in the set of Gold sequences. At 806,operations 800 further continue by applying a phase rotation to each ofthe Gold sequences in the set of Gold sequences. At 808, operations 800continue by modulating each of the of the Gold sequences in the set ofGold sequences by a Pi/2 binary phase shift keying modulation (BPSK)modulation with frequency domain spectral shaping. At 810, operations800 continue by selecting one or more sequences from the set ofmodulated Gold sequences based on a parameter. At 812, operations 800continue by transmitting the one or more sequences to a user equipment(UE) or a base station (BS).

In some embodiments, a UE (e.g., UE 120) or a BS (e.g., BS 110) maygenerate a reference signal for m tones. To generate the referencesignal, in some embodiments, the UE or the BS may generate a set of Goldsequences with length (2{circumflex over ( )}n−1). In some embodiments,each Gold sequence in the set may be generated by a different initialvalue for the registers or different primitive polynomial. For example,for each primitive polynomial, in each set of Gold sequences, there maybe 2{circumflex over ( )}n−1 sequences each having a length of2{circumflex over ( )}n−1. Each element in each of the Gold sequences iseither +1 or −1.

Next, in some embodiments, the UE or BS may extend or shorten the lengthof each of the Gold sequences to length m. In some embodiments, theextension of the length of a Gold sequence may involve a cyclicextension of the Gold sequence. In some embodiments, the shortening of aGold sequence includes truncating the last (2{circumflex over ( )}n−1-m)bits from the last.

Next, the UE or BS may optionally insert additional sequences at one ormore locations within the sequence. For example, the UE or BS may add aconstant (e.g., direct current (DC)) term to the extended or shortenedGold sequence. For example, a constant DC term may be added to eachextended or shortened Gold sequence (e.g., (Extended or Shortened Goldsequence)+(constant DC term)). The role of the constant DC term is tocompensate (−1) in the autocorrelation of each Gold sequence.

Next, in some embodiments, the UE or BS may introduce a phase rotationto each Gold sequence. For example, a phase rotation of pi/2 or −pi/2may be introduced. In some embodiments, let a(n) be the ((Extended orShortened Gold sequence)+(constant DC term)). In such embodiments, thephase rotation may then be either one of the following two:a(1),j*a(2),−a(3),−j*a(4),a(5),j*a(6),−a(7),  Option 1)a(1),−j*a(2),−a(3),j*a(4),a(5),−j*a(6),−a(7),  Option 2)

Next, in some embodiments the UE or BS may modulate each of the phaserotated Gold sequences by DFT-s-OFDM (Discrete FourierTransform-spread-Orthogonal Frequency Division Multiplexing) with FDSS.

FIG. 9 illustrates an example flow diagram for modulating a Goldsequence after introducing a phase rotation, as described above. Asshown in FIG. 9, in some embodiments, the sequence 902 in the timedomain is transformed into the frequency domain by applying a DFTalgorithm 904. Next, the sequence in the frequency domain may runthrough a FDSS low-pass filter 906. In some embodiments, FDSS filter 906may correspond to, for example, the following impulse response in thetime domain: [0.28, 1, 0.28] or [1 1]. In some embodiments, the FDSSlow-pass filter may be applied to the sequence while the sequence isstill in the time domain, prior to the application of the DFT. Next, atone mapper 908 may be applied to the tones in the sequence, wherebyeach tone in the sequence may be multiplied by a different constant.After the application of a tone mapper, an inverse Fast Fouriertransform (IFFT) algorithm 910 may be applied to the sequence formodulation. In some embodiments, a cyclic prefix 912 may also be addedafter modulation by the IFFT.

Next, in some embodiments, the UE or BS may select a subset from thesequence based on PAPR or Auto-correlation or Cross-Correlation orFrequency domain Flatness.

Accordingly, using Gold sequences, a reference signal is generatedhaving a design for Pi/2-BPSK modulation with FDSS with a higher PAPR.

FIG. 10 illustrates a wireless communications device 1000 (i.e., BS 10or UE 120) that may include various components (e.g., corresponding tomeans-plus-function components) configured to perform operations for thetechniques disclosed herein, such as one or more of the operationsillustrated in FIG. 8. The communications device 1000 includes aprocessing system 1014 coupled to a transceiver 1012. The transceiver1012 is configured to transmit and receive signals for thecommunications device 1000 via an antenna 1013. The processing system1014 may be configured to perform processing functions for thecommunications device 1000, such as processing signals, etc.

The processing system 1014 includes a processor 1009 coupled to acomputer-readable medium/memory 1010 via a bus 1024. In certain aspects,the computer-readable medium/memory 1010 is configured to storeinstructions that when executed by processor 1009, cause the processor1009 to perform one or more of the operations illustrated in FIG. 8, orother operations for performing the various techniques discussed herein.

In certain aspects, the processing system 1014 further includes agenerating component 1020 for performing one or more of the operationsillustrated at 802 in FIG. 8. Additionally, the processing system 1014includes an adjusting component 1022 for performing one or more of theoperations illustrated at 804 in FIG. 8. The processing system 1014further includes an applying component 1023 for performing one or moreof the operations illustrated at 806 in FIG. 8. The processing system1014 further includes modulating component 1025 for performing one ormore of the operations illustrated at 808 in FIG. 8. The processingsystem 1014 further includes a selecting component 1027 for performingone or more of the operations illustrated at 810 in FIG. 8. Theprocessing system 1014 further includes a transmitting component 1029for performing one or more of the operations illustrated at 812 in FIG.8.

The generating component 1020, the adjusting component 1022, theapplying component 1023, the modulating component 1025, selectingcomponent 1027, and the transmitting component 1029 may be coupled tothe processor 1009 via bus 1024. In certain aspects, the generatingcomponent 1020, the adjusting component 1022, the applying component1023, the modulating component 1025, selecting component 1027, and thetransmitting component 1029 may be hardware circuits. In certainaspects, the generating component 1020, the adjusting component 1022,the applying component 1023, the modulating component 1025, selectingcomponent 1027, and the transmitting component 1029 may be softwarecomponents that are executed and run on processor 1009.

The methods disclosed herein comprise one or more steps or actions forachieving the described method. The method steps and/or actions may beinterchanged with one another without departing from the scope of theclaims. In other words, unless a specific order of steps or actions isspecified, the order and/or use of specific steps and/or actions may bemodified without departing from the scope of the claims.

As used herein, a phrase referring to “at least one of” a list of itemsrefers to any combination of those items, including single members. Asan example, “at least one of: a, b, or c” is intended to cover a, b, c,a-b, a-c, b-c, and a-b-c, as well as any combination with multiples ofthe same element (e.g., a-a, a-a-a, a-a-b, a-a-c, a-b-b, a-c-c, b-b,b-b-b, b-b-c, c-c, and c-c-c or any other ordering of a, b, and c).

As used herein, the term “determining” encompasses a wide variety ofactions. For example, “determining” may include calculating, computing,processing, deriving, investigating, looking up (e.g., looking up in atable, a database or another data structure), ascertaining and the like.Also, “determining” may include receiving (e.g., receiving information),accessing (e.g., accessing data in a memory) and the like. Also,“determining” may include resolving, selecting, choosing, establishingand the like.

The previous description is provided to enable any person skilled in theart to practice the various aspects described herein. Variousmodifications to these aspects will be readily apparent to those skilledin the art, and the generic principles defined herein may be applied toother aspects. Thus, the claims are not intended to be limited to theaspects shown herein, but is to be accorded the full scope consistentwith the language claims, wherein reference to an element in thesingular is not intended to mean “one and only one” unless specificallyso stated, but rather “one or more.” Unless specifically statedotherwise, the term “some” refers to one or more. All structural andfunctional equivalents to the elements of the various aspects describedthroughout this disclosure that are known or later come to be known tothose of ordinary skill in the art are expressly incorporated herein byreference and are intended to be encompassed by the claims. Moreover,nothing disclosed herein is intended to be dedicated to the publicregardless of whether such disclosure is explicitly recited in theclaims. No claim element is to be construed under the provisions of 35U.S.C. § 112, sixth paragraph, unless the element is expressly recitedusing the phrase “means for” or, in the case of a method claim, theelement is recited using the phrase “step for.”

The various operations of methods described above may be performed byany suitable means capable of performing the corresponding functions.The means may include various hardware and/or software component(s)and/or module(s), including, but not limited to a circuit, anapplication specific integrated circuit (ASIC), or processor. Generally,where there are operations illustrated in figures, those operations mayhave corresponding counterpart means-plus-function components withsimilar numbering.

For example, means for transmitting and/or means for receiving maycomprise one or more of a transmit processor 420, a TX MIMO processor430, a receive processor 438, or antenna(s) 434 of the base station 110and/or the transmit processor 464, a TX MIMO processor 466, a receiveprocessor 458, or antenna(s) 452 of the user equipment 120.Additionally, means for generating, means for allocating, and/or meansfor including may comprise one or more processors, such as thecontroller/processor 440 of the base station 110 and/or thecontroller/processor 480 of the user equipment 120.

The various illustrative logical blocks, modules and circuits describedin connection with the present disclosure may be implemented orperformed with a general purpose processor, a digital signal processor(DSP), an application specific integrated circuit (ASIC), a fieldprogrammable gate array (FPGA) or other programmable logic device (PLD),discrete gate or transistor logic, discrete hardware components, or anycombination thereof designed to perform the functions described herein.A general-purpose processor may be a microprocessor, but in thealternative, the processor may be any commercially available processor,controller, microcontroller, or state machine. A processor may also beimplemented as a combination of computing devices, e.g., a combinationof a DSP and a microprocessor, a plurality of microprocessors, one ormore microprocessors in conjunction with a DSP core, or any other suchconfiguration.

If implemented in hardware, an example hardware configuration maycomprise a processing system in a wireless node. The processing systemmay be implemented with a bus architecture. The bus may include anynumber of interconnecting buses and bridges depending on the specificapplication of the processing system and the overall design constraints.The bus may link together various circuits including a processor,machine-readable media, and a bus interface. The bus interface may beused to connect a network adapter, among other things, to the processingsystem via the bus. The network adapter may be used to implement thesignal processing functions of the PHY layer. In the case of a userterminal 120 (see FIG. 1), a user interface (e.g., keypad, display,mouse, joystick, etc.) may also be connected to the bus. The bus mayalso link various other circuits such as timing sources, peripherals,voltage regulators, power management circuits, and the like, which arewell known in the art, and therefore, will not be described any further.The processor may be implemented with one or more general-purpose and/orspecial-purpose processors. Examples include microprocessors,microcontrollers, DSP processors, and other circuitry that can executesoftware. Those skilled in the art will recognize how best to implementthe described functionality for the processing system depending on theparticular application and the overall design constraints imposed on theoverall system.

If implemented in software, the functions may be stored or transmittedover as one or more instructions or code on a computer readable medium.Software shall be construed broadly to mean instructions, data, or anycombination thereof, whether referred to as software, firmware,middleware, microcode, hardware description language, or otherwise.Computer-readable media include both computer storage media andcommunication media including any medium that facilitates transfer of acomputer program from one place to another. The processor may beresponsible for managing the bus and general processing, including theexecution of software modules stored on the machine-readable storagemedia. A computer-readable storage medium may be coupled to a processorsuch that the processor can read information from, and write informationto, the storage medium. In the alternative, the storage medium may beintegral to the processor. By way of example, the machine-readable mediamay include a transmission line, a carrier wave modulated by data,and/or a computer readable storage medium with instructions storedthereon separate from the wireless node, all of which may be accessed bythe processor through the bus interface. Alternatively, or in addition,the machine-readable media, or any portion thereof, may be integratedinto the processor, such as the case may be with cache and/or generalregister files. Examples of machine-readable storage media may include,by way of example, RAM (Random Access Memory), flash memory, ROM (ReadOnly Memory), PROM (Programmable Read-Only Memory), EPROM (ErasableProgrammable Read-Only Memory), EEPROM (Electrically ErasableProgrammable Read-Only Memory), registers, magnetic disks, opticaldisks, hard drives, or any other suitable storage medium, or anycombination thereof. The machine-readable media may be embodied in acomputer-program product.

A software module may comprise a single instruction, or manyinstructions, and may be distributed over several different codesegments, among different programs, and across multiple storage media.The computer-readable media may comprise a number of software modules.The software modules include instructions that, when executed by anapparatus such as a processor, cause the processing system to performvarious functions. The software modules may include a transmissionmodule and a receiving module. Each software module may reside in asingle storage device or be distributed across multiple storage devices.By way of example, a software module may be loaded into RAM from a harddrive when a triggering event occurs. During execution of the softwaremodule, the processor may load some of the instructions into cache toincrease access speed. One or more cache lines may then be loaded into ageneral register file for execution by the processor. When referring tothe functionality of a software module below, it will be understood thatsuch functionality is implemented by the processor when executinginstructions from that software module.

Also, any connection is properly termed a computer-readable medium. Forexample, if the software is transmitted from a website, server, or otherremote source using a coaxial cable, fiber optic cable, twisted pair,digital subscriber line (DSL), or wireless technologies such as infrared(IR), radio, and microwave, then the coaxial cable, fiber optic cable,twisted pair, DSL, or wireless technologies such as infrared, radio, andmicrowave are included in the definition of medium. Disk and disc, asused herein, include compact disc (CD), laser disc, optical disc,digital versatile disc (DVD), floppy disk, and Blu-ray® disc where disksusually reproduce data magnetically, while discs reproduce dataoptically with lasers. Thus, in some aspects computer-readable media maycomprise non-transitory computer-readable media (e.g., tangible media).In addition, for other aspects computer-readable media may comprisetransitory computer-readable media (e.g., a signal). Combinations of theabove should also be included within the scope of computer-readablemedia.

Thus, certain aspects may comprise a computer program product forperforming the operations presented herein. For example, such a computerprogram product may comprise a computer-readable medium havinginstructions stored (and/or encoded) thereon, the instructions beingexecutable by one or more processors to perform the operations describedherein. For example, instructions for perform the operations describedherein and illustrated in FIG. 8.

Further, it should be appreciated that modules and/or other appropriatemeans for performing the methods and techniques described herein can bedownloaded and/or otherwise obtained by a user terminal and/or basestation as applicable. For example, such a device can be coupled to aserver to facilitate the transfer of means for performing the methodsdescribed herein. Alternatively, various methods described herein can beprovided via storage means (e.g., RAM, ROM, a physical storage mediumsuch as a compact disc (CD) or floppy disk, etc.), such that a userterminal and/or base station can obtain the various methods uponcoupling or providing the storage means to the device. Moreover, anyother suitable technique for providing the methods and techniquesdescribed herein to a device can be utilized.

It is to be understood that the claims are not limited to the preciseconfiguration and components illustrated above. Various modifications,changes and variations may be made in the arrangement, operation anddetails of the methods and apparatus described above without departingfrom the scope of the claims.

What is claimed is:
 1. A method for wireless communications for use by awireless communications device, the method comprising: generating a setof Gold sequences each having a length; adjusting the length of each ofthe Gold sequences in the set of Gold sequences, wherein the length is2{circumflex over ( )}n−1 bits, wherein the length is adjusted to mbits, wherein the length is adjusted by one of: extending the lengthusing a cyclic extension, or shortening the length by truncating a last(2n−1−m) number of bits; applying a phase rotation to each of the Goldsequences in the set of Gold sequences; modulating each of the Goldsequences in the set of Gold sequences; selecting one or more sequencesfrom the set of modulated Gold sequences based on a parameter; andtransmitting the one or more sequences to a user equipment (UE) or abase station (BS).
 2. The method of claim 1, wherein the parametercomprises at least one of peak-to-average power ratio, auto-correlation,cross-correlation, or frequency flatness.
 3. The method of claim 1,wherein the set of Gold sequences comprises 2n−1 Gold sequences, andwherein n is an integer.
 4. The method of claim 1, wherein thegenerating further comprises generating each Gold sequence in the set ofGold sequences using a different initial value for correspondingregisters or a different primitive polynomial.
 5. The method of claim 1,further comprising: inserting additional sequences at one or morelocations within each Gold sequence of the set of Gold sequences.
 6. Themethod of claim 5, wherein the additional sequences comprise a directcurrent (DC) constant term.
 7. The method of claim 1, wherein the phaserotation is by Pi/2 or −Pi/2.
 8. An apparatus, comprising: anon-transitory memory comprising executable instructions; and aprocessor coupled to the memory and configured to execute theinstructions to: generate a set of Gold sequences each having a length;adjust the length of each of the Gold sequences in the set of Goldsequences, wherein the length is 2{circumflex over ( )}n−1 bits, whereinthe length is adjusted tom bits, wherein the length is adjusted by oneof: extend the length using a cyclic extension, or shorten the length bytruncating a last (2{circumflex over ( )}n−1−m) number of bits; apply aphase rotation to each of the Gold sequences in the set of Goldsequences; modulate each of the Gold sequences in the set of Goldsequences; select one or more sequences from the set of modulated Goldsequences based on a parameter; and transmit the one or more sequencesto a user equipment (UE) or a base station (BS).
 9. The apparatus ofclaim 8, wherein the parameter comprises at least one of peak-to-averagepower ratio, auto-correlation, cross-correlation, or frequency flatness.10. The apparatus of claim 8, wherein the set of Gold sequencescomprises 2{circumflex over ( )}n−1 Gold sequences, and wherein n is aninteger.
 11. The apparatus of claim 8, wherein the processor configuredto generate the set of Gold sequences further comprises the processorconfigured to generate each Gold sequence in the set of Gold sequencesusing a different initial value for corresponding registers or adifferent primitive polynomial.
 12. The apparatus of claim 8, whereinthe processor is further configured to: insert additional sequences atone or more locations within each Gold sequence of the set of Goldsequences.
 13. The apparatus of claim 12, wherein the additionalsequences comprise a direct current (DC) constant term.
 14. Theapparatus of claim 8, wherein the phase rotation is by Pi/2 or −Pi/2.15. An apparatus comprising: means for generating a set of Goldsequences each having a length; means for adjusting the length of eachof the Gold sequences in the set of Gold sequences wherein the length is2{circumflex over ( )}n−1 bits, wherein the length is adjusted to mbits, wherein the means for adjusting is configured to adjust the lengthby one of: extending the length using a cyclic extension, or shorteningthe length by truncating a last (2{circumflex over ( )}n−1−m) number ofbits; means for applying a phase rotation to each of the Gold sequencesin the set of Gold sequences; means for modulating each of the Goldsequences in the set of Gold sequences; means for selecting one or moresequences from the set of modulated Gold sequences based on a parameter;and means for transmitting the one or more sequences to a user equipment(UE) or a base station (BS).
 16. The apparatus of claim 15, wherein themeans for generating is configured to generate each Gold sequences inthe set of Gold sequences using a different initial value forcorresponding registers or a different primitive polynomial.
 17. Anon-transitory computer readable medium comprising instructionsconfigured to be executed in a computer system to cause the computersystem perform a method for wireless communications, the methodcomprising: generating a set of Gold sequences each having a length;adjusting the length of each of the Gold sequences in the set of Goldsequences, wherein the length is 2{circumflex over ( )}n−1 bits, whereinthe length is adjusted to m bits, wherein the length is adjusted by oneof: extending the length using a cyclic extension, or shortening thelength by truncating a last (2{circumflex over ( )}n−1−m) number ofbits; applying a phase rotation to each of the Gold sequences in the setof Gold sequences; modulating each of the Gold sequences in the set ofGold sequences; selecting one or more sequences from the set ofmodulated Gold sequences based on a parameter; and transmitting the oneor more sequences to a user equipment (UE) or a base station (BS). 18.The non-transitory computer readable medium of claim 17, wherein thegenerating further comprises generating each Gold sequence in the set ofGold sequences using a different initial value for correspondingregisters or a different primitive polynomial.